Development of a surface-modified paper-based colorimetric sensor using synthesized Ag NPs-alginate composite

ABSTRACT

There has been an increase in the discovery and usage of sensors for the detection of chemical compounds in the field of analytical chemistry since the last several years. This has led to progressive research in nanotechnology for developing efficient nanomaterials for bio-chemical sensing applications. Thereby, a deft synthesis of silver nanoparticles (Ag NPs) under microwave irradiation was achieved using sodium alginate as a reducing and capping agent in a fast and cost-effective approach. As per the X-ray diffraction analysis, the average particle size of Ag NPs was found to be 10 nm. X-ray photoelectron spectroscpopy analysis showed characteristic peaks at binding energies of 368.10 and 374.11 eV indicating the formation of Ag NPs. The synthesized Ag NPs-alginate composite was further used to develop a paper-based sensor for the detection of H₂O₂. Detection of H₂O₂ is based on the discolouration of the Ag NPs-alginate composite modified paper sensor as a function of H₂O₂ concentration. The analysis of the decoloured paper strips was done by a smartphone camera and an RGB Colour Reader application (app) to measure colour intensity. The sensing characteristics were found in the range of 0.1–10 mM. The colour analysis revealed piecewise linear relationship of intensity of RGB to H₂O₂ concentration in the range of 0.1–1.5 and 2–10 mM with R² values of 0.97 and 0.9778, respectively. Owing to the high sensitivity, selectivity, and cost-effectiveness, the developed paper sensor can be a potential tool for real-time analysis of H₂O₂.

GRAPHICAL ABSTRACT

KEYWORDS:

• Paper-based sensor
• silver nanoparticles
• hydrogen peroxide detection
• smartphone
• chemical sensor

Acknowledgements

We thank Prof. Vinayak Ghaisas, Director and Dr Renu Vyas, Head of School, MIT BIO, for providing necessary facility to carry out the research work. We thank Dr Aruna Sivaram for her valuable inputs in manuscript preparation. We also thank Mr Amol Kahandal, Ms Mriti Agarwal, and Mrs Vedashree Sirdeshmukh for their assistance during the course of the research. We aknowledge the Sophisticated Analytical Instrument Facility (SAIF) at IIT Bombay and CSIR-NCL Pune for providing HR-TEM and XPS analysis facility, respectively.

Disclosure statement

No potential conflict of interest was reported by the authors.